In part for ease of installation, modular carpet has traditionally been installed in aligned rows and columns, with the edges of each tile aligned with the edges of adjacent tiles (“conventional carpet tile installation method”). Conventional carpet tile has also historically been a product that sought to mimic the appearance of broadloom carpet and to hide or at least de-emphasize the fact that the product was modular. Achieving this result has required, at minimum, that carpet tiles or modules be placed in a flooring installation with the same orientation that the modules had at the time they were produced. This is because conventional production techniques, particularly including tufting techniques, cause the carpet pile to lean or have a nap direction. This property of conventional carpet modules causes a tile within a field of tiles to have a different appearance, particularly under certain lighting and viewing conditions, if it is oriented in a different direction than the tiles with which it is placed. Other considerations, such as the presence of a pattern that spans more than one tile in the web from which the tiles are cut, have also sometimes required that not only the rotational orientation of tiles in an installation be the same but for the tiles to be located in particular relative positions. Indeed, schemes for insuring or facilitating placement of modular carpet in predetermined relative positions (as well as rotational orientation) have been developed. One such approach is suggested in U.S. Pat. Nos. 6,197,400 and 6,203,879, both to Desai.
Textile face modular flooring designers have recently begun to design flooring and flooring installations that do not seek to mask, but rather celebrate, the modularity of the flooring. For instance, modules are installed “quarter-turned” with each tile position rotated 90° relative to each adjacent tile. In other instances, module edges are emphasized to achieve an installation appearance similar to that of ceramic tile separated by grout.
There continues, however, to be substantial demand for flooring designs that do not visually emphasize the modularity of flooring components and instead appear to have a design that spans the entire flooring installation or part of the flooring installation rather than appearing to be confined to individual modules.
Uniform rotational orientation during module installation is facilitated by the presence of direction indicia on the modules, which usually is placed on the back or underside of the modules, and requires careful attention to rotational orientation during installation. Installation in predetermined relative module positions requires even more attention during installation and frequently is very difficult, if not impossible, even with tile edge designs like those described in U.S. Pat. Nos. 6,197,400 and 6,203,879, because of room shape or size and the presence of obstructions.
Carpet tile and other textile face modular flooring has to be highly uniform in size and shape and has to have edge structures that present a uniform floor covering when edges of adjacent tiles are abutting. These requirements make it a practical necessity for such products to be produced by forming a web of tile material that is at least somewhat wider than the width of one flooring module, and preferably a bit wider than some multiple of modules, and then cutting modules from that web. For instance, carpet tile is typically produced by manufacturing a web a bit more than six feet wide and then cutting from it tiles that are eighteen inches square, or by manufacturing a web a bit more than two meters wide and then cutting from it tiles that are one-half meter square. In each case, four tiles can be obtained across the web. While it is relatively easy to cut modules from such a web that have a desired size with a high level of accuracy, it is difficult to position the longitudinal cuts or module separation lines accurately with respect to predetermined positions on the web. It is likewise difficult to position the transverse cuts or module separation lines accurately with respect to predetermined positions on the web, at least without substantial material waste.
Another approach to some of the challenges associated with modular flooring described above has been to produce first a web, and then modules of flooring, that are uniform in color and carry no pattern, so that only nap direction is important and there are no problems of registration between a tile pattern or design and the tile edges. This makes relative tile position irrelevant. In other instances, tile producers have sought to address the design-to-module registration issues by first producing a uniform color tile or module and then printing a design on the face of the tile that is positioned by reference to the tile edges after the tile is cut from the web. There are, however, design, cost and functional limitations associated with printing on textile face modular flooring. A third approach has been to use relatively small design elements so that such elements at a tile edge will not look odd near tile edges or if they are cut by tile edges.
Some design types present particular problems for use on modular flooring. One such difficult design type is parallel stripes. To ensure a fluid appearance in a flooring installation, the tiles cut from a web having uninterrupted stripes extending along its length obviously must be oriented so that all of the stripes of the tiles are oriented in the same direction. However, this alone will not achieve an aesthetically desirable installation appearance.
First, attention has to be paid to the appearance at the places where side-by-side tiles are abutting in an installation so that there is not an out-of-place or odd appearing stripe at that location. Additionally, attention may be drawn to the place where top-to-bottom tile abutment occurs, i.e, where the ends of stripes on one tile meet the ends of stripes on another tile.
One could imagine a design having uniform-width, parallel stripes that fall in precisely the same locations on each tile. It would then be possible to position such tiles in the same orientation on a floor to produce a uniform pattern of uninterrupted, uniform, parallel stripes across a room. Such carpet tiles would be very difficult to produce, however, using conventional production techniques where a carpet web is produced and then cut into tiles, because it is difficult to achieve identical tiles.
One reason for this is that it is difficult to locate the cuts that separate the web into tiles precisely in predetermined locations. This will result in different width stripes at tiles edges (where the stripes are of uniform width on the carpet web). Additionally, unless tiles are positioned so that the stripes on one tile are precisely aligned with the stripes on an adjacent tile, the appearance of continuous stripes on the web will not be reproduced on the floor. This is difficult to do unless the tiles are reassembled exactly as they came from the web. It is unlikely that stripes will align from one tile to the next because, among other reasons, of variation in the location of longitudinal cuts on the web. Imprecise cutting can result in stripes of a tile appearing offset from stripes of adjacent tiles, thereby betraying seams and ruining the appearance of continuous stripes in the flooring installation. Additionally, as noted above, the position of the longitudinal cuts relative to the stripes into which or next to which they fall can create a stripe that appears to be wider or narrower than those in the design (except, of course, where the modules are assembled on the floor in the same side-by-side location they had in the web and the split stripe is re-assembled). Given the necessity but difficulty of attaining cutting precision with conventional striped designs, flexibility in placement of the tiles having a conventional striped pattern of equal-width, continuous stripes is severely limited.
Consequently, there remains a need for modular flooring design and production techniques that enable the creation of flooring designs having parallel stripes notwithstanding the above-described and other constraints of conventional modular carpet construction and installation.